1. Field of the Invention
This invention relates to quaternized fatty acid triethanolamine ester salts ("esterquats") with improved solubility in water which are obtained by esterifying selected mixtures of linear and branched fatty acids with a triethanolamine component and then quaternizing the resulting esters by methods known per se, to a process for their production, to the use of the new esterquats for the production of surface-active formulations and to the use of the fatty acid mixtures for the production of water-soluble esterquats.
2. Discussion of Related Art
Quaternized fatty acid triethanolamine ester salts, so-called "esterguats", are cationic surfactants which are acquiring increasing significance by virtue of their excellent fabric-softening properties and their high ecotoxicological compatibility. The publications by O. Ponsati in C.R. CED Congress, Barcelona, 1992, page 167 and R. Puchta in C.R. CED Congress, Sitges, 1993, page 59, are cited as representative of the literature available on the subject.
The esterquats are normally prepared by a two-stage process in which triethanolamine is first partly esterified with fatty acids and the reaction product is then quaternized with methyl chloride or preferably dimethyl sulfate in isopropyl alcohol. Low-viscosity concentrates of the esterquats in isopropyl alcohol with a solids content of up to 85% by weight can be obtained in this way. However, products of satisfactory odor, i.e. alcohol-free products, are required for many applications, particularly in the cosmetics field. If the isopropyl alcohol is removed after quaternization, commercial esterquats are solid which is detrimental to their processability. Another disadvantage is that the known water-free commercially available esterquats are difficult to disperse in water and that, in particular, the production of concentrates is not possible without the assistance of auxiliaries.
Now, the problem addressed by the present invention was to provide new esterquats which would have low viscosities in water-free form, would be readily processable to water-containing concentrates and would exhibit advantageous performance properties.